The basic problem is to determine the extent to which the premature infant's isolation and separation from parents (a consequence of being kept in the nursery) influence the mother-infant interaction and affect subsequent cognitive development. In this study comparisons will be made between two groups of prematures that differ in length of the stay in the isolation nursery but are at low risk of neurological damage. The following areas will be assessed: 1. The quality of the mother's interaction with her infant. 2. The mother's perception of the infant's temperament and early personality. 3. The infant's early cognitive and cognitive-motivational development.